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Biomedical subjects

I Forouzan

Publications and source records attributed to I Forouzan.

At least 19 recordsLinked to original sources
PubMed2000

Photon migration through fetal head in utero using continuous wave, near infrared spectroscopy: clinical and experimental model studies.

Near infrared (NIR) measurements were made from the maternal abdomen (clinical studies) and laboratory tissue phantoms (experimental studies) to gain insight into photon migration through the fetal head in utero. Specifically, a continuous wave spectrometer was modified and employed to make NIR measurements at 760 and 850 nm, at a large (10 cm) and small (2.5/4 cm) source-detector separation, simultaneously, on the maternal abdomen, directly above the fetal head. A total of 19 patients were evaluated, whose average gestational age and fetal head depth, were 37 weeks +/- 3 and 2.25 cm +/- 0.7, respectively. At the large source-detector separation, the photons are expected to migrate through both the underlying maternal and fetal tissues before being detected at the surface, while at the short source-detector separation, the photons are expected to migrate primarily through the superficial maternal tissues before being detected. Second, similar NIR measurements were made on laboratory tissue phantoms, with variable optical properties and physical geometries. The variable optical properties were obtained using different concentrations of India ink and Intralipid in water, while the variable physical geometries were realized by employing glass containers of different shapes and sizes. Third, the NIR measurements, which were made on the laboratory tissue phantoms, were compared to the NIR measurements made on the maternal abdomen to determine which tissue phantom best simulates the photon migration path through the fetal head in utero. The results of the comparison were used to provide insight into the optical properties and physical geometry of the maternal and fetal tissues in the photon migration path.

Adult↗
PubMed1998

Intrauterine growth retardation in a woman with primary hyperparathyroidism. A case report.

BACKGROUND: Primary maternal hyperparathyroidism leads to increased serum calcium levels, which suppress fetal parathyroid development, leading to hypocalcemia in the neonate. CASE: In a pregnant woman, hypercalcemia was observed to be related to a parathyroid adenoma that was surgically removed at 15 weeks' gestation. Subsequently, hypocalcemia developed, requiring calcium replacement. There was marked premature calcification of the placenta, noted to be grade 3 at 23 weeks, and this was thought to be related to the severe intrauterine growth retardation that later developed. Preterm premature rupture of membranes occurred at 33 weeks, and a growth-retarded neonate with a small, calcified placenta was delivered. CONCLUSION: Pregnancies associated with hyperparathyroidism have been found to be complicated by an increased incidence of spontaneous abortion, stillbirth and neonatal tetany. There may also be an increased risk of fetal intrauterine growth retardation. Serial ultrasonography to evaluate fetal growth and antenatal testing should be considered.

Adenoma↗
PubMed1997

Hydrops fetalis: recent advances.

Hydrops fetalis is a morbid condition caused by a wide variety of fetal, placental, and maternal diseases. Mortality is high and depends on the gestational age at the time of occurrence and underlying etiology. Although the condition was described more than 300 years ago, recent advances in obstetric ultrasound, prenatal diagnostics have made it possible to differentiate various etiologies involved. It is also possible to treat some of these fetuses prenatally. In utero medical and surgical therapy is presently done in some centers. However, the majority of cases diagnosed remain untreatable. Early diagnosis of untreatable cases allows parents to make informed choices about subsequent management. Recent advances are covered in this review.

Gestational Age↗
PubMed1996

Reduction of right atrial peak systolic velocity in growth-restricted discordant twins.

OBJECTIVE: The objective of this study was to measure blood flow velocity changes through the tricuspid valve in intrauterine growth-restricted twins. STUDY DESIGN: Discordant twins were evaluated by measurement of tricuspid valve flow velocities. Twin pairs with one intrauterine growth-restricted fetus caused by uteroplacental insufficiency and one appropriately grown fetus were included in the analysis. Fetuses with chromosomal or structural abnormalities and confirmed twin-twin transfusion syndrome were excluded. Eighteen pairs met these criteria. Student's t test was used for comparison of flow velocities. RESULTS: Peak ventricular diastolic flow velocities through the tricuspid valve in the twin with intrauterine growth restriction and the appropriately grown twin were 35.8 +/- 4.43 cm/sec and 34.0 +/- 6.7 cm/sec, respectively (p = 0.35). The atrial peak systolic flow velocity values were 42.1 +/- 1.2 and 50.3 +/- 1.2, respectively (p = 0.049). CONCLUSIONS: The velocity of blood flow through the tricuspid valve during atrial systole is lower in growth-restricted twins than in appropriately grown cotwins when growth restriction is caused by uteroplacental insufficiency. Its potential in differentiating discordancy from the other causes remains to be explored.

Atrial Function, Right↗
PubMed1996

Fetal middle cerebral artery blood flow velocities in pregnancies complicated by intrauterine growth restriction and extreme abnormality in umbilical artery Doppler velocity.

If they are not delivered in a timely fashion, pregnancies complicated by severe intrauterine growth restriction (IUGR) can lead to fetal loss. Conventional fetal well-being tests, including ultrasound measurement of fetal growth rate, biophysical profile, nonstress test, and contraction stress test are used to manage these pregnancies. Some fetuses delivered based on abnormal fetal well-being tests show long-term sequelae. A better understanding of the malfunction of the placenta and its effect on the fetus is desperately required for better management of these cases. We are reporting our experience of 6 such pregnancies followed by fetal middle cerebral artery (MCA) blood flow velocity measurements. There was significant decrease in MCA flow velocities in all of these fetuses compared to normal population (p < 0.05). Reverting to normal values occurred prior to the appearance of abnormal conventional tests, on average 4 days earlier. In other words, normalization of MCA flow velocities was a harbinger of fetal jeopardy. Although our observation includes a small number of patients, there is a potential for use of MCA blood flow velocity measurement to aid us in understanding and managing fetuses with IUGR. This needs to be evaluated in a larger study.

Blood Flow Velocity↗
PubMed1996

Prevention of Rh isoimmunization after spontaneous, massive fetomaternal hemorrhage.

Massive fetomaternal hemorrhage has been associated with numerous risk factors and can occur spontaneously. The risk is probably greater when a woman who is Rh negative has an ABO-compatible fetus. We report the case of a gravid, A-negative unsensitized patient who came to the hospital at term complaining of decreased fetal movement over the previous 24 hours. During evaluation, the fetal heart rate was found to have decreased beat-to-beat variability and repetitive late decelerations, and the mother was delivered of a 3,005 gA-positive neonate (by cesarean section) with a hemoglobin level of 2.9 g/dL. An acid elution test showed 400 mL of fetal blood in the maternal circulation, and the patient received 23 ampules (6,900 micrograms) of Rh immune globulin postpartum. The patient's condition was observed for 156 days after delivery; she did not become sensitized to the Rh factor. A massive fetomaternal hemorrhage can occur without any antecedent risk factors, with a risk of subsequent morbidity to the neonate. Sensitization can be prevented by prompt administration of adequate amounts of Rh immune globulin.

ABO Blood-Group System↗
PubMed1996

Pregnancy outcome in active duty seagoing women.

The effect of working on the outcome of pregnancy has been previously addressed. Very few studies have looked at the effect of specific work conditions on pregnancy, and to our knowledge no studies have reviewed the pregnancy outcomes of women stationed on-board a submarine tender. In order to study the pregnancy outcomes of such women, we performed this study. All women (N = 140) who delivered in the 18 months between February 1991 and August 1992 and were stationed on-board either the USS E.S. Land or the USS Hunley were studied. Their pregnancy, delivery, and newborn records were reviewed. These women received excellent prenatal care. However, many risk factors were identified that were much higher than national averages. We conclude that pregnant sailors stationed on-board submarine tenders are at high risk for certain adverse pregnancy outcomes. Further studies are needed to determine if this difference persists when sailors at sea commands are compared to sailors stationed at shore commands.

Adult↗
PubMed1996

Postcesarean endometritis. Clinical risk factors predictive of positive blood cultures.

OBJECTIVE: To identify peripartum risk factors that are predictive of positive blood cultures in patients with postcesarean endometritis. STUDY DESIGN: A retrospective review of 179 patients diagnosed with postcesarean endometritis was conducted. Patients with positive and negative blood cultures obtained at the time of diagnosis were compared. Patient's charts were reviewed for intrapartum, intraoperative and postpartum factors. Chi-square and nonpaired Student's tests were used when appropriate, with P < .05 considered significant. RESULTS: During this period, 179 (20%) postcesarean patients developed endometritis. One hundred sixty-eight (94%) of those patients had blood cultures. Eleven (6.5%) were positive; however, one of these grew a skin contaminant and was disregarded. When patients with positive blood cultures were compared to those with negative blood cultures, length of labor, number of vaginal examinations, postoperative day when the diagnosis was established, estimated blood loss at the time of cesarean delivery, presence of intrapartum chorioamnionitis, number of hours of ruptured membranes, white blood cell count at the time of diagnosis, use of prophylactic antibiotics, development of wound infection or other infectious etiologies were not shown to be predictive. There were no positive blood cultures among patients with a temperature < 38.5 degrees C. At a temperature < 38.8 degrees C, 1/126 (0.79%) had a positive blood culture. At a temperature > or = 38.8 degrees C, 9/42 (21.4%) had a positive blood culture (P < .001). Approximately $5,890 was spent on obtaining positive blood cultures in patients with temperatures < 38.8 degrees C. In contrast, $218 was spent per positive blood culture obtained from patients with a temperature > or = 38.8 degrees C. CONCLUSION: The traditional practice of obtaining blood cultures at a temperature > or = 38.0 degrees C is not justified but elevating the threshold to 38.8 degrees C is equally effective and less costly.

Anti-Bacterial Agents↗
PubMed1995

Absence of end-diastolic flow velocity in the umbilical artery: a review.

The objective of this review was to find the clinical relevance of the absence of end-diastolic flow velocity in the umbilical artery. Search was conducted through MEDLINE using unabridged MEDLINE Knowledge Finder (Aries System Corp., North Andover, MA). All the manuscripts published in English language within last 10 years (1983-1992) were included in the review process. There has been no report of umbilical artery absent-end diastolic velocity before 1983. It was extremely difficult to draw a conclusion because a majority of the available reports in the literature are either case reports or retrospective analyses. However, for the practical purposes it can be concluded that after viability these pregnancies should be followed by intense (daily) fetal well-being surveillance with conventional antenatal tests. Those who improve their end-diastolic velocity should be allowed to continue the pregnancy as long as antenatal testing is promising. Persistence of absent end-diastolic velocity may be an indication for delivery at a gestational age when there is reasonable chance of survival. Cytogenetic evaluation and anatomical survey of these fetuses by ultrasound is recommended. Long-term follow up of surviving infants needs to be studied. It is impossible for a single institution to accumulate enough cases for adequate outcome evaluation. A randomized prospective trial to assess the management of pregnancies with absent end-diastolic velocity in the umbilical artery would be difficult. Some might even consider such a study unethical. Until such a study is performed, an international registry would be helpful for collecting data about the perinatal outcomes and management of such patients.

Blood Flow Velocity↗
PubMed1993

Stability and change of interest in obstetrics-gynecology among medical students: eighteen years of longitudinal data.

PURPOSE: To compare the percentage of students who maintain interest in specializing in obstetrics-gynecology during medical school with the percentages of students maintaining interest in other selected specialties, and to examine changes of interest from obstetrics-gynecology to other specialties and from other specialties to obstetrics-gynecology. METHOD: A longitudinal cohort study comparing the stabilities of students' interests in obstetrics-gynecology and in other specialties was performed by using data on 3,889 graduates of 18 classes of Jefferson Medical College of Thomas Jefferson University between 1975 and 1992. RESULTS: The percentage of students who maintained interest in obstetrics-gynecology, as measured at the beginning and end of medical school, was 19%, compared with 40% for internal medicine and surgery, 39% for family medicine, and 22% for pediatrics. By the time they graduated, some students who had planned as freshman to pursue obstetrics-gynecology had changed their interests to internal medicine (19%), surgery (17%), family medicine (8%), or pediatrics (7%). In turn, obstetrics-gynecology attracted students who had initially expressed interest in other specialties: 17% from family medicine, 14% from surgery, 12% from internal medicine, and 8% from pediatrics. Despite the low percentage of students who maintained interest in obstetrics-gynecology, the overall percentage of students interested in obstetrics-gynecology at the time of graduation was somewhat greater than the percentage of students interested at the start of medical school. CONCLUSION: That only about one-fifth of the students initially interested in obstetrics-gynecology maintained their interest, and that many students' interests changed from one specialty to another, suggest that factors contributing to changes in interest need further investigation.

Career Choice↗
PubMed1993

Umbilical artery and ductal blood flow velocities in patients treated with aspirin and prednisone for presence of anticardiolipin antibody.

Fifteen patients with previous pregnancy losses and positive plasma anticardiolipin antibody (ACA) were treated with prednisone (15 mg/day) and aspirin (80 mg/day). We measured Doppler velocimetries of umbilical artery and ductus arteriosus at intervals of 2 to 3 weeks starting from 20 weeks of gestation until delivery. Umbilical artery systolic/diastolic ratios (S/D) and maximum systolic velocities of ductus arteriosus did not differ from normal values. There were no poor outcomes in the treated group. ACA positive patients with previous poor pregnancy outcome when treated with prednisone and aspirin have umbilical artery and ductal flow velocities similar to those of the normal population.

Abortion, Habitual↗
PubMed1992

Fetal abdominal echogenic mass: an early sign of intrauterine cytomegalovirus infection.

BACKGROUND: Recent advances in ultrasound technology have made it possible to diagnose fetal diseases much earlier in pregnancy. Reports have indicated that intrauterine infections, specifically cytomegalovirus, can be diagnosed prenatally by ultrasound. CASE: We encountered two cases in which cytomegalovirus infection was associated with hyperechoic areas in the fetal abdomen. CONCLUSION: Hyperechoic areas in the fetal abdomen may be an early sign of fetal cytomegalovirus infection. Persistence of this sign may indicate a mild form of infection. Disappearance of these hyperechoic areas in subsequent ultrasonographic examinations and development of other ultrasound signs may indicate severe infection and poor prognosis.

Adult↗
PubMed1991

Fetal well-being: nonimaging assessment and the biophysical profile.

All of the testing methods described above are very good at predicting continued fetal health when test results are reassuring. Each test also suffers from a very poor ability to predict compromise when results are abnormal. Thus, the primary value of antepartum fetal monitoring is in identifying those pregnancies that do not require immediate intervention and may be allowed to continue. Certainly, all pregnant women (regardless of risk status) should monitor fetal movement as part of their fetal surveillance. For patients at risk, a variety of testing schemes are available using combinations of the NST, CST and BPP. There are several reasons for using the NST as the primary testing method for those at risk. Even a small antenatal testing area can accommodate three or four FHR monitors, and a single antenatal testing nurse can perform several NSTs at a time. Because the BPP requires an ultrasound machine and a trained technician to perform, and because only one BPP can be done at a time, many obstetricians who do their own in-office fetal testing are unable to adopt BPP testing as their primary means of surveillance. Additionally, it is more economical to use the NST than the BPP for first-line testing. Assuming charges of $150 and $300 for the NST and BPP, respectively, and assuming that 20% of NSTs are nonreactive and require a BPP for second-line testing, the weekly cost of testing 100 patients is $21,000 for the NST and $37,500 for the BPP. This increase-in-testing cost must be balanced against the small improvement in perinatal mortality rates achieved with the use of the BPP. Because it must be performed in a hospital setting and takes an average of 90 minutes to complete, the CST is more expensive and time-consuming than either the NST or BPP and it is less frequently used as the primary method of fetal testing. In the past the CST was the most commonly used secondary test after a nonreactive NST, but use of the BPP in this situation has now become commonplace. Although the CST still has an important role in fetal testing, the BPP is better suited for use in this setting because of its technical ease and low incidence of abnormal results. Thus, many centers use the NST as the primary mode of testing for the fetus at risk, often with a sonographic assessment of AFV.(ABSTRACT TRUNCATED AT 400 WORDS)

Female↗
PubMed1991

Measurement of systolic-diastolic ratio in the umbilical artery by continuous-wave and pulsed-wave Doppler ultrasound: comparison at different sites.

Analysis of umbilical artery flow velocity waveforms, especially systolic-diastolic (S-D) ratio, can predict some pregnancy abnormalities. Most of the earlier studies did not specify the exact segment of umbilical artery sampled. We studied 53 normal singleton pregnancies between 18-41 weeks' gestation to compare S-D ratio measurements of the umbilical artery at different sites: 1) abdominal insertion site, 2) placental insertion site, 3) mid-cord, and 4) an undetermined site. The mean S-D ratio was significantly different (P less than .01) at various segments of the umbilical artery--higher near the abdominal insertion site when compared with the mid-cord, near-placental, and undetermined sites. The S-D ratio at mid-cord was higher than at the undetermined site and the placental insertion site. The near-placental-site S-D ratio was not different from the undetermined site. A lower S-D ratio at the undetermined site may not adequately reflect the true physiologic status of the fetus. Specifying the site of measurement should be an integral part of any report, in order to describe accurately the pathophysiology of fetoplacental circulatory diseases.

Blood Flow Velocity↗
PubMed1991

Can umbilical and arcuate artery Doppler velocimetry predict fetal distress among prolonged pregnancies?

We studied umbilical and arcuate artery Doppler velocity waveforms in 30 uncompromised prolonged pregnancies (greater than 41 weeks of gestation). Normal systolic/diastolic ratios in these vessels had a negative predictive value similar to other antepartum tests. The positive predictive value, though, was not high enough to consider Doppler studies of the umbilical and arcuate arteries as the only test to identify the group of prolonged pregnancies that have uteroplacental insufficiency. There is a possibility that the combination of Doppler velocimetry with other antepartum tests may improve our ability to predict poor outcome. Further study is needed.

Arteries↗
PubMed1991

Smoking and buccally administered nicotine. Acute effect on uterine and umbilical artery Doppler flow velocity waveforms.

The effects of maternal smoking and buccal nicotine exposure on uterine and umbilical artery blood flow velocity waveforms were studied in 47 healthy women during late pregnancy. Systolic:diastolic ratios of recorded waveforms were calculated before and after each woman smoked one cigarette containing 1.2 mg of nicotine. The same protocol was followed at a subsequent clinic visit, when each woman chewed a piece of nicotine polacrilex containing 2 mg of nicotine. No significant changes could be induced in either nonsmokers or prior smokers, nor were any significant changes measured in the uterine vessels of any patient subgroup. A significant decrease (P less than .01) in umbilical artery diastolic blood flow velocities was measured after smoking in all habitual smokers after chewing nicotine polacrilex and in those who smoked greater than 10 cigarettes per day (P less than .05). All the measured changes returned to baseline levels by 10 minutes after cessation of exposure. Similar changes in the umbilical artery flow velocity waveforms after exposure to a cigarette and nicotine polacrilex implicated nicotine as a probable cause. Failure to observe significant changes except in habitually smoking women suggests a receptor-mediated response. The finding of altered umbilical artery flow velocity waveforms in the absence of demonstrable changes in the uterine vessels indicates a direct toxic effect of maternal nicotine exposure on the fetal cardiovascular system.

Administration, Buccal↗